Graduate Studies

 

First Advisor

Christine Wittich

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Civil Engineering

Date of this Version

12-9-2024

Document Type

Dissertation

Citation

A dissertation presented to the faculty of the Graduate College at the University of nebraska in partial fulfillment of requirements for the degree of Doctor of Philosophy

Major: Educational Studies (Educational Leadership and Higher Education)

Under the supervision of Professor Deryl K. Hatch-Tocaimaza

Lincoln, Nebraska, February 2020

Comments

Copyright 2024, the author. Used by permission

Abstract

This dissertation aims to enhance the performance and structural integrity of civil infrastructure systems through two primary goals. The first goal is to develop and rigorously validate end-to-end frameworks for full-field monitoring of the dynamic response of civil structures via Ground-based Lidar (GBL) scanners. GBL can be employed to sample point clouds at a high sampling rate for dynamic data collection, which addresses the limitations of using contact-based sensors in structural health monitoring (SHM) applications used for early-detection of structural damage. The second goal of this dissertation concerns the challenges associated with constructing bridges in phases, so they can remain partially open to traffic during construction. While this approach mitigates traffic disruptions, it raises concerns about the structural integrity of newly constructed segments due to traffic-induced vibrations. Therefore, to address these concerns, the second goal of this dissertation aims to generate a fundamental understanding of the transmission of traffic-induced vibration, the extent of degradation on phased-construction bridge decks, and the impact of potential mitigation measures. Concerning the first goal of this dissertation, a novel framework was developed to characterize the dynamics of structures using remotely sensed dynamic point clouds collected via GBL. An extensive experimental campaign was conducted to validate the proposed framework across a range of GBL- and structure-based parameters in a controlled laboratory environment. The proposed framework was used to monitor the full-field dynamic response of two real-world structures as full-scale validation case studies. Furthermore, to facilitate the remote dynamic monitoring of structures via GBL sensors mounted on unmanned aerial vehicles (UAVs), a point-cloud-based framework for ego-motion compensation was developed. With respect to the second objective of this dissertation, extensive field monitoring tests were conducted to monitor the dynamic response of two real-world phased-construction bridges in the field. Furthermore, an extensive experimental study was conducted to study the impact of applying various mitigative traffic-control measures during phased construction on the integrity and performance of bridge decks. This was accomplished through full-scale dynamic and static testing of large-scale bridge deck specimens. The experimental program aimed to replicate a typical phased-construction scenario of a bridge deck in a laboratory environment.

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